SStolen

iTrader: (22)

I know some of the cranks are the same but which one should I use for my turbo motor? I need a new one. Planning on 600rwhp now and 850 later.
I believe I remember seeing that one had holes for better oil flow or something and the other didn't. Is that correct and pro's and con's?

Just tell me what Harlen was using. lol.

y2khawk

iTrader: (5)

4.8 is a different beast, shorter stroke. The 5.3/5.7/6.0 all start as the same casting, the cars are drilled down the center (main journals) for weight reduction. No special oiling that I know of. I ran a 5.7 crank in the car. The truck is using the 5.3 crank that came in the truck.

Country Boy

iTrader: (24)

wouldnt the 6.0 crank be more stable as the core is solid. It doesnt add any rotating mass since its all in the center.

y2khawk

iTrader: (5)

i guess it might be. If memory serves from my college days (many beers ago) torsional stiffness goes up at radius^4. It might only be the second power, i'm an EE after all But that .5" radius at the center is mostly along for the ride IMHO.

I personally wouldn't freak over one or the other. The simple fact you're pushing a cast factory crank over 1k HP should out weigh the fact it might have a hole bored down the center

Country Boy

iTrader: (24)

True. lol I didnt know if the cylinder pressures would cause any distortion having the hollow crank.

LTLHOMER

iTrader: (10)

t = TC/J

T-torque
t-torsional strength
C-outer radius
And J is pi/2 * (Radius-outer ^4 - radius-inner^4) which is the polar moment of intertia IIRC.

So boring a hole through the middle will have very minute effects on the overall strength of the crankshaft.

You have a good memory of ME stuff for an EE!

Phate

iTrader: (2)

Thank god for you *******...I hate math

427

iTrader: (3)

The crank with the hole down the center would be better for what you are doing. The hole down the center helps balance blowby/windage problems that come from a skirted block with wet sump oiling.

Kurt

Country Boy

iTrader: (24)

Interesting! I have a 6.0 in my 347 because when I built the motor I was planning on spraying the **** out of it and was told that the solid crank would be better.

quicksilverado

iTrader: (8)

Does a crank need to be rebalanced if it is used in a different setup other than what it was intended for? ie a 5.7 crank in a 6.0 block since the pistons are a different weight.

99Fbody99

Absolutely, even with piston/rod changes withing the same family.

Hell, you should see how much mallory is take to balance a 5.3 crank with 5.7 rotating harware

Dave

rons 00z

iTrader: (10)

i always thought it's easier to bend a solid bar instead of a hollow one since theres going to be more surface area affected(outer and inner) i would imagine it's the same idea for a crank.....does that sound right?

LTLHOMER

iTrader: (10)

Cranks don't experience much bending stress though...predominantly torsional/transverse shear I'd say.

I will look that up though it does sound familiar in terms of strictly bending stress.